Bridge specs

musicofanatic

I recall following some dialog on bridges a while back, but I don't remember any specifics about the space between the feet of the bridge. Is there an optimum length for this arch, and for the height of the arch (the distance between the top of the gtr. and the bridge in this arch)? Also is the arch between the feet what is being refered by the use of the term "hollow", as in "hollow bridge" (I saw this on one builder's web site describing the bridge he sells)? Or does the term indicate that additional material is removed from the underside of the bridge? I'm replacing the factory bridge on a Gitane, which is much too low. The bridge appeared to be somewhat "hogged out" underneath.
Thanks for any responses,
musicofanatic

Craig Bumgarner

I'm not a great expert, but I recently made my own bridge and I'll give these questions a shot.

The length of the arch is pretty much driven by where the bridge lands on the short braces under the top which are there for the purpose of supporting the bridge. If you go by the old bridge, you should be okay. These braces are usually about 1/2" wide and on some bridges, the part outboard of the braces is also relieved (arched) a little also. Unless you built the guitar yourself, it can be hard to define exactly where these braces are, so using the old bridge as a guide is a good way to go.

How deep should the arch be? I don't really know. The Saga bridges have a high arch, higher than any others I've seen. The other Selmer bridges I have seen have a lower arch, about 3mm. I'm not convinced that there is really anything wrong with the higher arch per se as long as the bridge is sufficiently rigid to support the strings.

The "hollow" being refered to is the "hogged out" area under the bridge, not the arch.

All this hollowing and arching is to lighten the bridge and make it more reponsive. The idea is to make the bridge rigid enough to support the strings, dense enough to transmit sound well, but light enough to be set in motion quickly. Hollowing and arching both work toward this direction by putting the mass in the most advantagious postion structurally.

Craig

musicofanatic

Thanks, Craig. I appreciate your concise and informative response to my questions.
musicofanatic

Josh Hegg

I don't have the place in front of me but I think according to the Selmer plans:

Hight of Arch - 6mm (this is up to you. It really makes little difference)
Channel - 7mm - I know this is the correct measurement

Cheers

Craig Bumgarner

Josh & Musicofanatic:

Got the Charle plans in my hands! 8) The plan dimensions both the hollow and the arch from the top. The depth (height?) of the hollow is 7mm from the top! (not the underside of the arch), the bottom of the arch is shown as 3mm off the deck.

Craig

Josh Hegg

Will I was close.... not really but... All I know is that the hollow seems really deep when your doing it. I have played around with depth of the hollow and I think the deeper or the lighter the bridge the better he sound. Also I use some really hard rosewood. I got a bunch of ends from a local wood carving shop. Great stuff. some of the hardest wood I have worked. Not hard to work but hard. It really has a tone when you bounce it on the work bench. I nice ring to it.

Cheers